Figure 2

Diffraction patterns recorded at different delay times τ and the corresponding one-dimensional profiles. (a) The unperturbed pattern recorded before pump laser irradiation, pre-shocked state. A clear Debye–Scherrer ring indicates the Bragg peak for the (110) plane of iron with a bcc structure at 35.62°. (b) At τ = 10 ps, the ring becomes slightly wider. (c) At τ = 50 ps, an increase in baseline intensity in the higher angle region is observed relative to the initial Bragg peak. (d) At τ = 70 ps, a prominent new peak appears in the higher angle region. (e) At τ = 150 ps, the intensity of the new peak increases. (f) At τ = 500 ps, the peak shifts to a lower angle. This new peak indicates the Bragg one for the compressed bcc (110) plane. (a′–f′) are one-dimensional profiles corresponding to (a–f) where the XRD patterns obtained on the two-dimensional detector are intensity-integrated in the δ direction, 2θ is converted to d-spacing using λ = 2dsinθ relationships, where λ is the wavelength of the XFEL, d is a d-spacing of a lattice, θ is the Bragg angle, and the intensity is normalised to the maximum value. (g) One-dimensional profiles for a series of delay times.